Ashton Carter is Ford Foundation Professor of Science and International Affairs at Harvard University's John F. Kennedy School of Government and a former Assistant Secretary of Defense. John Deutch is Institute Professor of Chemistry at the Massachusetts Institute of Technology and a former Director of Central Intelligence and Deputy Secretary of Defense. Philip Zelikow, a former member of the National Security Council staff, is White Burkett Miller Professor of History and Director of the Miller Center of Public Affairs at the University of Virginia.

IMAGINING THE TRANSFORMING EVENT

Terrorism is not a new phenomenon. But today's terrorists, be they international cults like Aum Shinrikyo or individual nihilists like the Unabomber, act on a greater variety of motives than ever before. More ominously, terrorists may gain access to weapons of mass destruction, including nuclear devices, germ dispensers, poison gas weapons, and even computer viruses. Also new is the world's dependence on a nearly invisible and fragile network for distributing energy and information. Long part of the Hollywood and Tom Clancy repertory of nightmarish scenarios, catastrophic terrorism has moved from far-fetched horror to a contingency that could happen next month. Although the United States still takes conventional terrorism seriously, as demonstrated by the response to the attacks on its embassies in Kenya and Tanzania in August, it is not yet prepared for the new threat of catastrophic terrorism.

American military superiority on the conventional battlefield pushes its adversaries toward unconventional alternatives. The United States has already destroyed one facility in Sudan in its attempt to target chemical weapons. Russia, storehouse of tens of thousands of weapons and material to make tens of thousands more, may be descending into turmoil. Meanwhile, the combination of new technology and lethal force has made biological weapons at least as deadly as chemical and nuclear alternatives. Technology is more accessible, and society is more vulnerable. Elaborate international networks have developed among organized criminals, drug traffickers, arms dealers, and money launderers, creating an infrastructure for catastrophic terrorism around the world.

The bombings in East Africa killed hundreds. A successful attack with weapons of mass destruction could certainly take thousands, or tens of thousands, of lives. If the device that exploded in 1993 under the World Trade Center had been nuclear, or had effectively dispersed a deadly pathogen, the resulting horror and chaos would have exceeded our ability to describe it. Such an act of catastrophic terrorism would be a watershed event in American history. It could involve loss of life and property unprecedented in